Thanks for trying it. It is a bit difficult, but I appreciate you looking past that to the concept :). If you get into the groove, it helps. Also, out of the sixteenth notes in each measure, you can input on beat 15, or 16 of the previous measure, or beat 1 or 2 of the next measure, for a total of 1 quarter-note's-worth of input time.
Thanks for thinking it's fun! That's the goal! Cheers!